3GPP (3rd Generation Partnership Project) is a project that examines and produces the specifications of a mobile communication system based on a network in which W-CDMA (Wideband-Code Division Multiple Access) and GSM (Global System for Mobile Communications) are developed. In the 3GPP, the W-CDMA system is standardized as a third-generation cellular mobile communication system, and its serves have been launched one after another. Moreover, HSDPA (High-speed Downlink Packet Access) in which its communication speed is further increased is also standardized, and its serves have been launched. In the 3GPP, a mobile communication system (hereinafter referred to as “LTE-A (Long Term Evolution-Advanced” or “Advanced-EUTRA”) is being examined which utilizes evolution of a third-generation radio access technology (hereinafter referred to as “LTE (Long Term Evolution” or “EUTRA (Evolved Universal Terrestrial Radio Access”) and a wider frequency band to realize higher-speed data transmission/reception.
As the communication system of the LTE, an OFDMA (Orthogonal Frequency Division Multiple Access) system in which subcarriers orthogonal to each other are used to perform user multiplexing and an SC-FDMA (Single Carrier-Frequency Division Multiple Access) system are being examined. In other words, in the downlink, the OFDMA system, which is a multicarrier communication system, is proposed, and in the uplink, the SC-FDMA system, which is a single carrier communication system, is proposed.
As the communication system of the LTE-A, in the downlink, the introduction of the OFDMA system is being examined, and in the uplink, in addition to the SC-FDMA system, the introduction of a Clustered-SC-FDMA (Clustered-Single Carrier-Frequency Division Multiple Access; which is also referred to as a DFT-s-OFDM with Spectrum Division Control or a DFT-precoded OFDM) is being examined. In the LTE and the LTE-A, the SC-FDMA system and the Clustered-SC-FDMA system proposed as the uplink communication system, according to characteristics of a single carrier communication system (single carrier characteristics), can suppress low a PAPR (Peak to Average Power Ratio: transmission power) when data (information) is transmitted.
Moreover, in the LTE-A, an examination is being performed in which a plurality of frequency bands that has the same channel structure as the LTE and is contiguous and/or non-contiguous (which can be referred to as a carrier) (hereinafter referred to as a “Cell” or a “Component Carrier (CC)”) is compositely used and is utilized as one wide frequency band (referred to as Cell aggregation or Carrier aggregation). Furthermore, in order for a base station apparatus and a mobile station apparatus to more flexibly use a wide frequency band to perform communication, it is proposed that a frequency band used for downlink communication and a frequency band used for uplink communication are made different in frequency bandwidth (Asymmetric cell aggregation or Asymmetric carrier aggregation) (Non-patent document 1).
Furthermore, in the LTE-A, it is proposed that the mobile station apparatus applies MIMO SM (Multiple Input Multiple Output Spatial Multiplexing) to transmit Downlink Transport Block (Downlink TB) to the mobile station apparatus (Non-patent document 2). Here, the MIMO SM refers to a technology in which a plurality of signals is multiplexed and transmitted/received for the channels of a plurality of spatial dimensions realized by a plurality of transmission antenna ports and a plurality of reception antenna ports. Here, the antenna port refers to a logical antenna used for signal processing, and one antenna port may be formed with one physical antenna or may be formed with a plurality of physical antennas. In addition, one transmission antenna port may correspond to one reference signal.
For example, the base station apparatus applies the MIMO SM to a Physical Downlink Shared Channel (PDSCH), and thereby can transmit transport blocks for a plurality of (for example, up to two) downlink shared channels (DL-SCHs) to the mobile station apparatus. In other words, the base station apparatus applies the MIMO SM to the PDSCH, and thereby performs transmission to the mobile station apparatus with a plurality of (for example, two) Code Words (CWs).
Furthermore, in the LTE-A, as a method of the mobile station apparatus to transmit, to the base station apparatus, information indicating an ACK/NACK (Positive Acknowledgement/Negative Acknowledgement, an ACK signal or a NACK signal) in a HARQ for the downlink transport block, the transmission of the information indicating the ACK/NACK by Channel Selection is proposed (Non-patent document 3).